The PCMCIA card, which is a credit card-sized device, has been developed and standardized by an international association so that it can be utilized universally. This card plugs into a slot arranged on the computer which is a host device. The purpose of using such a card is to provide access to items such as additional random access memory (RAM), hard disk space, a modem, or, at times, even a network.
Most portable computers utilized today provide slots for PCMCIA cards (hereinafter called PC cards), and even some desktop computer models are beginning to appear on the market with such slots available. The PC card has a plurality of terminals, generally at one end of the card, and these terminals correspond and cooperate with opposite terminal arranged in the host device, such as the portable computer. Generally, the card contains the female connectors, and the host device contains the male connectors. A recent article discussing the development and use of PC cards, appears in the publication Electronics Now, Jun. 1995, pages 31-36. This article points out the different sizes of PC cards which have been standard by the Personal Computer Memory Card International Association.
There are, at present, at least three different size cards Type I, Type II and Type III. The external size of the cards are the same, roughly 54.times.85.6 mm. However, the thickness of the Type I card is 3.3 mm; the Type II card 5.0 mm and the Type III card 10.5 mm. The Type I card is generally used for providing increased memory since it is too thin to carry many additional elements. The Type II card, being somewhat thicker, can hold additional memory and input/output features. The thickest, Type III, card is large enough to accommodate a complete hard drive or a radio communication device. It should be noted that even though the three cards are three different thicknesses, the connecting area is still the same so that a PC slot in a host device can make connections to any one of the three cards since the interconnect area is still the same dimension.
The connectors or terminals provided with the normal PC cards make electrical contact with the host device so that the circuit or circuits arranged on the card can be integrated and utilized with the circuits already on the portable or desktop computer serving as the host device. Such terminals provide good electrical connections. However, for radio frequency purposes, in which high frequencies are to be transmitted between the circuit or circuits on the card and the circuit or circuits in the host device, such mechanical connections are not satisfactory.
Attempts have been made to use coaxial connectors which could provide an RF connection, but because of the size of the card, space is generally not available and such arrangements are only awkwardly utilize for examination,(see the Article mentioned above which illustrates a digital video PC card having RF coaxial connectors). Such card has a cable attachment to accommodate the RF coaxial connectors.
Other uses have been proposed for the PC card, such as a radio transceiver for industrial, scientific and medical (ISM) applications between 2.4 GHz and 2.435 GHz. Such cards would be Type III PC cards.